Smog in Western US Starts Out As Pollution in Asia, Researchers Say: NPR

“The U.S. is producing less air pollution, but smog levels are still rising in the western U.S. because of pollutants released in Asian countries that then drift over the Pacific Ocean. Researchers say their findings show the importance of a global approach to preserving air quality…”Scientists found Asian air pollution contributed as much as 65 percent of an increase in Western ozone in recent years,” NPR’s Rob Schmitz reports from Shanghai. “China and India, where many consumer products are manufactured, are the worst offenders.”NPR